This invention relates to hydroforming methods and apparatus.
It is known in the art relating to hydroforming to provide a die set with upper and lower dies forming multiple die cavities in which hydroforming of multiple components is performed simultaneously. The hydroforming process involves applying internal hydraulic pressures in the die cavities, often on the order of 10,000 psi (69xc3x97106 Pa). The press in which the die set is mounted must apply sufficient force to maintain the dies closed against the internal forces developed in the totality of all the die cavities which are, in effect, mounted in parallel within the press. For larger components, this results in a requirement for very high press loadings, calling for a very large and expensive press.
The present invention provides a method and apparatus for hydroforming multiple components in a press containing dies having multiple die cavities arranged to limit the press loading to essentially that required to hydroform a single component in a single die cavity. This is accomplished by aligning the multiple die cavities in series in the press so that the separating forces of only the die members at the ends of the series act against the press with a force equal to only the separating force of a single die cavity. The forces of the intermediate dies are internally balanced by the forces acting in the adjacent die cavities and so do not add any additional force to that of the single cavity acting on the press.
The apparatus accordingly includes: a plurality of mating hydroforming die pairs engagable to form a plurality of aligned and spaced hydroforming die cavities having parting lines of the die pairs extending generally laterally to the direction of alignment of the die pairs; a press operative to load the engaged die pairs in the direction of alignment; and means for simultaneously hydroforming components in the die cavities while the dies are loaded.
The method involves: arranging in essentially linear alignment die pairs forming a plurality of separate die cavities, with the die pairs positioned such that internal separating loads in the die pairs act in alignment with the die cavities; and loading the die pairs in a press in the direction of alignment of the die cavities while simultaneously hydroforming components in each of the die cavities.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.